Method of and apparatus for preparing stencil-sheets for duplicating.



, E. w. HILL. METHOD OF AND APPARATUS FOR PREPARING STENCIL SHEETS FOR DUPLICATTNG. APPLICATION FILED SEPT. 18, 19I5.

11,1 88,937.. Patented June 27,1916.

ATTORNEY ED ARD w. HILL, or CHICAGO,

ILLINOIS, AssIGnon TO A. n. DICK COMPANY, or

CHICAGO, ILLINOIS, A CORPORATION OF-ILLINOIS.

METHOIl or AND APPARATUS roR PREPARING STENCIL-SHEETS FOR DUPLICATING.

Specification of Letters Patent.

PatentedJuneEY, Iain.

Application filedseptember 18, 1915. Serial I\To..51,324.-

To all whom it may concem Be it known that I, EDWARD W. HILL, a

citizen of the United States, residin at Chicago, in the county of Cook and tate 5 of Illinois, haveinvented .certainncw and useful Improvements in Methods of and] Apparatus for Preparing'Stencil-Sheets for Duplicating, of which the following is a specification. The invention concerns particularly the process of stencil-duplication now in common use, in which is employed a stencil sheet of open porous material coated with a .compound consisting largely of coagulated protein. Such stencil-sheets are normally dry but hygroscopic and before being. stencilized are softened by the application of moisture thereto. In what is known as the dermatype process,, such a stencil-sheet iscombined with a backing of relatively 4 hard impervious material, bearing upon the surface next adjacent to the under side ofthe stencil-sheet'a sheet "of absorbent material to which, the stencil-sheet having been lifted, the moisture is applied, after which the stencil-sheet is pressedinto contact with such material to transmit the moistureto such sheet. The type or other characters are then formed, by pressure, in

" i the stencil-sheet, after which such sheet may be placed in a duplicating-machine and multiple copies made by passing ink v through the interstices therein. This-proc-- ess is used very largely for typewriter sten- 7 cil-duplication; also for autographic work,-

4 for architectural and engineering drawings and the like. In many cases, drawings are made upon the stencil-sheet and thereafter the-same sheet is typed in a writing-ma- 1chine, vas, forexample, to add-descriptive v notes to the drawlng. In the copying of a drawing upon such a stencil-sheet, an approved method'involve's placing the stencilsheet, a suitable backing and the drawing to be copied upon a glass plate, anelectric lamp being placed below the same, so as to project the lines of the copy through the backing and, to some extent, through the stencil-sheet, permitting such linesto be followed upon the latter by means of a sultable stylus, whereby passages are opened in the stencil-sheet for the subsequent transmission of ink in the production of multiple copies.

In the utilization of the process above v sult in the drying out'of the sheet before the referred to for certain purposes, notably the duplication of drawings and similar work, difficulty has been experienced not only in applying the moisture evenly to the stencil-sheet but also in retaining the moisture, so as/ to maintain the stencil-sheet in proper condition for stencilization, through an extended period of time. A single application of moisture to the stencil-sheet, while sufficient for a short time, is apt to reoperation of stencilizing has been completed. Successive applications of moisture are not only'annoying and t'me-consuming D but are also apt to result in ack of uniformity in the finished work. Again, where the preparation of the drawing itself consumes considerable time and yet after the drawing has been completed descriptive matter must be typed uponthe stencil-sheet this involves additional application of molsture before the sheet is placed in the writingmachine and with the/same result, z'.e., lack of uniformity. These and otherdifiiculties hereinafter pointed out are overcome under 3 the present invention, inv which, in conjunction preferably with a composite stencilsheet consisting of thestencil-sheet proper and a 1' suitable backing secured thereto, I employ a thin, flexible and preferably transparent sheet of a suitablematerial such as celluloid, such sheet being placed between the stencil-sheet and the backing and having its upper surface, or both upper and lower surfaces, roughened, as, for instance, by pressing the same against sand-blasted 7 metal or glass. The moisture, instead of being applied to the backing-sheet or toan absorbent sheet-laid thereon, is applied to the upper surface of the celluloid sheet and the stencil shcet pressed down in contact therewithiand smoothed out, so that there i shall be a uniform application of moisture throughout the area of the stencil-sheet to soften the material thereon preliminarily to the stencilizing operation. The minute depressionsin the uppper surface of the celluloid sheet serve primarily to hold a sufficient quantity of.\the moistening fluid to maintain the stencil-sheet in usable condition throughout an extended period of time, and secondarily to maintainthe sheet fiat and resist the tendency thereof during a prolonged operation thereon, to become wrinkled or distorted. The celluloid sheet may, if

desired, advantageously be roughened upon both sides, not' only to avoid placing the wrong side next adjacent to the under side 4 of the stencil-sheet (asmight inadvertently be done were but one side roughened), but

also to prevent the tendency of such sheet,"

during the 'stencilizing process, to creep or becomedisplaced upon the underlying-backv ters Patent No. 1,101,259, granted June 23rd,"

ing-sheet or the therewith.

The invention is illustrated in the acabsorbent sheet combined I companying drawing, in which- Flgure 1 1s a plan view and Fig. 2 a perspective view, illustrating. a composite stencil-sheet provided with the roughened intermediate plate or sheet hereinabove described. I

In these drawings, the stencil-sheet proper,

. 1, is shown as attached at its forward edge,

2, as by a suitable adhesive, to the attachment edge 3 of the backing-sheet 4:. Such backing-sheet may be of ordinary, fairly stifl paper, or the upper surface thereof may, if.desired,- be provided with an attached absorbent surface, such as is described in Let- 1914. Between the stencil-sheet 1 and the backing sheet 4.- is interposed the sheet 5,

1 preferably of thin, light, transparent and flexible material, such as celluloid, and provided on either the upper surface or-on both upper and lower surfaces with a roughened exterior formed by suitable means, such as that hereinabove specified. Celluloid possesses the desired characteristics and is capable, in addition, of maintaining its roughened exterior, and may, therefore, be advantageously employed in practising the process herein disclosed. The characteristics of lightness, thinness and-flexibility are desirable from the standpoint of convenience in use. The characterlstic of transparency is particularly availed of where, ashereinabove indicated, it is desired to tracemaps, drawings, etc., upon a stencil-sheet by means of a copy placed below the same, the lines upon such copy being projected by a suit- "with the margins of the stencil-sheet not to be utilized for the formation of stencil in terstices therein. I consider it important, however, that the roughening of thecelluloid sheetbe not a coarse roughening but of very considerable fineness (such as results from the roughening means above described), for while, under my invention, it is the purpose that the minute depressions shall hold a sufiicientquantity of the moistening fluid'to maintain the stencil-sheet in usable condition throughout an extended period of time, it is also desirable that during the stencilizing process the point of the stylus (used for autographic work or for ruling, drawing or sketching) shall pass easilyand smoothl over the surface of the stencil-sheet, practlcally unaffected by the minute roughness of the underlying celluloid sheet.

The use of thin and flexible material, such as celluloid, for the interposed sheet or plate is desirable, since it may not easily be broken, does not require too great separation of the stencil-sheet and backing, and may be held immovable, at one point, relatively to the underlying backing and copy and yet raised at another point either for direct inspection of such copy or to adjust stencil-sheet, backing and interposed sheet ample, a drawing is to be formed upon the stencil-sheet, the procedure is as above indicated, the celluloid sheet being laid upon the absorbent backing and the moisture apfiplied thereto for transmission to the stencilsheet. If, now, it be desired to add to the drawing depicted upon the stencil-sheet. descriptive memoranda, either autographically orby means ofa writing-machine, this may be done either without further moistening or the celluloid sheet may be removed and the moistening fluid applied to the absorbent backing, after which, the stencil-sheet being pressed into contact with such backing so as to renew the application of moisture to such sheet, the additional memoranda may be placed upon the stencil-sheet in any desired manner, such, for instance, as by the useof astylus or by placing the composite sheet in a writing-machine and typing thereon.

Having now described my invention, what I claim as new therein and desire to secure by Letters Patent is as follows 1. The method of preparing a stencil-v sheet for duplicating, which involves applying moisture to the roughened'surface of a sheet of thin, hard material, superimposing pressure,

2. The method of preparing a stencilsheet for duplicating, which involves applying moisture to the roughened surface of a sheet of thin, hard flexible material, superimposing a stencil-sheet upon said surface,

and then stencilizing said stencil-sheet by pressure, substantially as set forth.

3. The method of preparing a stencilsheet for duplicating, which involves applying moisture to the roughened surface of a sheet of thin, hard, transparent material, superimposing a stencil-sheet upon said surface, and then stencilizing said stencil-sheet by pressure, substantially as set forth.

4. The .method of preparing a stencilsheet for duplicating, which involves applying moisture to the roughened surface of a sheet of thin, hard, flexible, transparent ma- 3 terial, superimposing a stencil-sheet upon said surface, and then stencilizing said stencil-sheet by pressure, substantially as set forth.

5. The method of preparing a stencilsheetfor duplicating, which involves applying moisture to the minutely roughened surface of a thin sheet of flexible non-absorbent hard material, superimposing a stencilsheet upon said surface, and then stencilizing said stencil-sheet by forming desired characters thereon under application of pressure, substantially as set forth.

6. In stencil-duplication," the combination with a sheet ofthin, hard, flexible, nonabsorbent material having minute depressions formed on, and closel its upper surface, adapted 0 receive moisture, of astencil-sheet superimposed thereon, said depressions being sufficiently minute so that a stylus point may pass easily and smoothly over the surface of the sheet, substantially as set forth.

7. In stencil-duplication, the combination with a sheet of hard, transparent material having a roughened surface, of a stencilsheet superimposed upon said surface, sub- 45 stantially as set forth.

8. In stencil-duplication, the combination with a sheet of thin, hard, flexible, transparent material having a roughened surface,

of a stencil-sheet superimposed upon said 50 surface, substantially as set forth.

This specification signed and witnessed this 15th day of September, 1915.

Witnesses:

J osErH TEAL, W. G. ARNOLD.

arranged over stencil- EDWARD W. HILL. L i 

